Causes of ACL Injuries (Part 5)

Here is part 5 of my knee pain and knee injury series.

If you missed part 1, you can see it here. If you missed part 2, you can see it here. If you missed part 3, you can see it here.  If you missed part 4, you can see it here.

Risk Factors and Incidence

It is estimated that the overall ACL injury rate in the United States is about 200,000 annually. This figure suggests that 1 in 300,000 individuals in the U.S. will sustain an ACL injury for the first time each year. ACL injuries commonly occur between the ages of 14 and 29 years, occurring in non-athletes and athletes. Those engaged in football, soccer, basketball, soccer and skiing activities are the most susceptible to ACL injury in the athlete group.

Female athletes are more susceptible to ACL injuries than male athletes performing similar sporting activities and training. It is estimated that female athletes are 2 to 8 times more likely to sustain ACL injuries when compared with their male counterparts (Souryal & Adams, 2009).

Many factors have been attributed to the increased susceptibility of women to ACL injuries. Females have a narrower femoral notch, or the space at the bottom of the thigh bone where the ACL runs. This tight fit may cause increased friction between the ACL and femur during knee movements. Another possible cause is the greater Q angle, or the angle between the quadriceps and the patella tendon, in women.  A larger angle is partly caused by a woman’s wider pelvis. This increases the risk for greater stress and ACL injuries. Other factors include increased joint laxity, inadequate strength and impaired neuromuscular coordination.


A complete physical assessment and a review of the mechanism of injury are conducted in the diagnosis of an ACL injury. Imaging tests may be ordered to verify the diagnosis and determine the extent of the damage. Some techniques, such as the Lachman test, pivot shift test and the anterior drawer test, may be performed to determine the occurrence of any knee problem.

Treatment and Management

Minor ACL injuries are highly responsive to conservative treatment methods, most especially if they are appropriately utilized and given in a timely manner. With compliance, full mobility should be achieved within 2 to 8 weeks. For complete ACL tears, a surgical reconstruction is recommended, followed by a rehabilitation that may last between 6 to 12 months.
If you have sustained an ACL injury, it is best to immediately discontinue your activity. Although weight bearing is possible and knee function is not significantly diminished, it is best to completely rest the involved knee until the pain and swelling subside. Immobility during acute pain promotes the healing process, improving recovery time. During recovery, be sure to avoid exercises that hyperextend and rotate the knee.

Apply cold or ice packs to the knee for 15 to 20 minutes every 1 to 2 hours for the first 24 to 48 hours to reduce the pain and swelling. Only apply heating pads or hot towels to the injured knee 48 to 72 hours after the injury. Heat relaxes the muscles and relieves stiffness. Alternating ice and heat applications 48 hours after the injury may also relieve the pain.

Elevate the knee above the heart and wrap the knee with an ACE or elastic bandage to reduce and limit the swelling. Non-steroidal anti-inflammatory medications, such as ibuprofen and aspirin, may be taken to reduce pain and inflammation. For severe or uncontrolled pain, cortisone injections may be administered for immediate relief of pain.

This is part 5 of this series. I will be putting up the next part over the next few days.
If you are interested in knee pain, knee injuries or ACL injuries, these other posts may interest you:

ACL Injuries in Female Athletes

3 ACL Exercise Mistakes

What to do about Knee Pain?

To Leg Press or Squat if You Have an ACL Injury?

NCAA and ACL Injuries

Downhill Walking Good After ACL Surgery?

Knee Injuries and Exercises with Kevin Yates

If you are looking for stuff with more details on knee pain and ACL injuries, you can attend the live course called Exercise Rehabilitation of the Knee or instantly download my video presentation on Exercises for Prevention, Rehabilitation and Overcoming Knee Injuries.

Rick Kaselj, MS